The ad hoc-charge against the SMHM [“Standard Model Higgs Mechanism”] is interesting from a philosophical point of view on several grounds. First, the claim that our currently best theory of fundamental particle physics is based on an ad hoc-hypothesis sounds alarming and is certainly worthy of consideration in itself. Second, there exists a longstanding philosophical debate about the notion of adhocness, to which eminent philosophers of science such as Popper, Lakatos, Schaffner, Grünbaum, Leplin and others have made important contributions. This gives rise to the question of whether the SMHM qualifies as “ad hoc” according to any of these philosophers’ accounts of adhocness, and what the possible ramifications would be. Third, it seems natural to ask what impact the recent experimental discovery of a Higgs-like particle at the LHC has on the status of the ad hoc-charge against the SMHM.This concept of adhocness may seem stupid, but it is the main reason those philosophers of science credit Einstein for special relativity. See for examples Brush, Singh, Hawking, Zahar, Kacser, Kragh, and Rigden.
Einstein made his reputation on his most famous paper, his 1905 special relativity paper. But he had trouble explaining how it was an advance over previous work. Lorentz had the FitzGerald contraction, local time, constant speed of light, rejection of aether motion, relativistic mass, transformation of Maxwell's equations, and explanation of Michelson-Morley. Besides all that, Poincare had the clock synchronization, relativity principle, viewing the aether as a convention, E=mc2, Lorentz group, spacetime, non-Euclidean geometry, electromagnetic covariance, and gravity waves. Others at the time described Einstein's paper as just a presentation of Lorentz's theory, and no one thought that it was as advanced as Poincare's work.
Einstein's response was that Lorentz's theory was "ad hoc", and that he did not understand Poincare's 4D theory. Philosophers gradually picked up on this concept, and now a majority of Einstein scholars agree. They say that Lorentz was ad hoc in the sense that he paid close attention to experiments like Michelson-Morley. Einstein's innovation, they say, was to present relativity as a paradigm shift that ignores experiment. They blame Lorentz and Poincare for failing to be true believers in the new relativity religion, because they both said that experimental evidence could prove them wrong.
Philosophers went on to say that the great scientific revolutions are reworkings of previous theories that have no measurable advantages. Einstein's genius was to detach himself from the physical world. Theoretical physicists have largely adopted this view, and get most excited about untestable ideas like string theory, multiverse, many-worlds, etc.
All of this is horribly misguided. Special relativity comes to us from Lorentz, Poincare, and Minkowski. Einstein had almost zero influence on the creation or acceptance of the theory. Lorentz and Poincare were very much concerned with explaining the physical world when they developed the theory. Those who use Einstein as an example of the merits of incommensurable paradigm shifts are just wrong.
(Einstein was influential in acceptance of general relativity, but that was because he pointed to empirical evidence. With hard evidence, it was not one of those Kuhnian paradigm shifts that the philosophers love.)
All of this is detailed in my book, How Einstein Ruined Physics, and on this blog.
So the invention of the Higgs mechanism in the 1960s was ad hoc in the sense that it was an attempt to explain how a gauge field could be short-range, and the weak and strong forces were observed to be short-range. How is this a criticism? Of course physicists respond to data when formulating their theories. That is how it has always been done, until Einstein wasted away his post-1925 life on unified field theories, and string theorists took over in 1980 or so.